Process of producing salts of oxyacids of chlorin.



UNITED sTArEs PATENT OFFICE.

ARTHUR EDWARD GIBBS, OF NIAGARA FALLS, NEW' YORK, ASSIGNOR TO THE NA'llONAL ELECTROLYTIC COMPANY,' OF NIAGARA FALLS, NEW

YORK, A CORPORATION OF NEW YORK.

PROCESS OF PRODUCING SALTS OF oxYAc Ds 0 CHLORIN.

Specification of Letters Patent.

Patented Aug. 7; 1906 Application filed March 26. 1904. Serial No. 2001144 To all whom it may concern:

Be it known that I, ARTHUR EDWARD GIBBS, a subject of the King of Great Britain, residing at Niagara Falls, in the county of Niagara and State of New York, have invented a Process of Producing Salts of Oxyacids of Chlorin, of which the following isa specification. 1

These salts have hitherto been produced on a commercial scale by electrolyzing a solution of a chlorin by the use of platinum anodes in a cell without a diaphragm and crystallizing out the chlorate thus produced, the best results being obtained when the operation is conducted at temperaturesof about 70 to 80 ccntigradc.

Taking the potassium salt as an exani le the reactions *may be represented by the 01- lowing equations:

1. KCl:K+Ol.

2. K+H2O=KHO+H.

. 3KClO+heat in the electrolytic cell:

'KOlOz-l-QKC]. The potassium chlorid splits up into potassium and chlorin, but the chlorin reacts at the moment of formation so quickly to form (as in equation 3) potassium hypochlorite, with the potash made according to equation 2, that no chlorin is evolved. Three molecules of hypochlorite then decornpose,for1n ing chlorate and chlorid according to equa tion 4.

My invention results in producing chlorates at a current efiiciency which may be as high as ninety-six per cent. or ninety-eight per cent. and the operation is conducted in such a manner that carbon or graphite anodes may be used to advantage for the electrolytic step of the process. Such anode so far as I am aware have never before been used on a commercial scalev in connection with the production of chlorates. This enormously reduces the cost of plant necessary to produce these salts.

Hitherto in experinienting' with graphite anodes for the production of chlorates two principal causes have operated to break down or disintegrate such anode. First, the

gas evolved at its surface breaks away parti cles of carbon, and in the case of oxygen com blues with it chemically, formlng an oxid of carbon, and, secondly, the high temperature necessary to obtain a good efiiciency tends to break up the graphite. To overcome the first difficulty, I reduce the amount of gas formed at the anode to a minimum by mak ing of the reaction between chromate and chlorin discovered by me and described in my copending application, Serial No. 195,994, filed March 1, 1904, and which consists, essentially, in the simultaneous production of bichromato and chlorate by actingupon a chromate with chlorin. B conducting this operation as described in t io above applica- 't1on i. e., by-elcctrolyzing a solution of a chlorid in the presence of a chromate in a diaphragm cel1onl a very small quantity of gas is evolved at t e anode, which when using graphite anodes adds greatly to their hie. The second trouble is overcome by conducting the electrolysis at a comparatively low temperature, preferably below 37 centigrade, removing the liquor from the neighborhood of the electrodes and heating. .The

following reactions occur in the cell at low temperature: e 1. KOl K-i-Gl.

2. 6K2GrOi+3Clz- 3191C 1'2O1'+ 3 K01 O BKOl A ortion of the hypochloritessplit up in the cell oven at the low temperature. The remainder do so when heat is applied, both reactions occurring according to equation 4, page 1. I prefer to use a diaphragm-cell, as the output of product per horse-power hour is greatly increased thereby, owing .to eliminating the reducing action of the hydro gen at the cathode upon the chlorate or hypochlorite at the anode.

When the chlorin is produced electrolytically in the presence of a-chromate at a tem perature above. 37 centigrade, the final result of the change at the anode maybe eX- pressed by the following equations:

GKzOIOrl- SO12 3K2Or2O7+5KO1+KClO3.

This may be easily.

' been converted to bichromate.

."ec'rion in Lette rs Patent No. 827,721.

After or during the above change some or all of the alkali formed at the cathode or from an outside source .may be allowed to react with the bichromate formed at the anode, producing chromate according to the following equation:

2KHO+ KZCrZOT QKA 1101+ H2O.

In this way the birhromaie ma be continually changed tO C-lllfilllittfi wit 10111: the increase of either in solution while the chlorate formation proceeds. The presence of a chromium compound is not absolutely necessary to produce a high elliciencv. may have present a trace of a chlorid, the h drate of the metal with which it is combiner being sparingly soluble or insoluble in thes0lution-- for instance, calcium ehloridand conducting the electrolysis at a'temperature preferably below 37 centigrade, raisim the temperature oi the solution after electrolysis.

lhe calcium hydrate being practically insoluble is deposited at the cathode, leaving its chlorln free at the anode. 'lhis chlorm dissolves in the solution at the temperature at which the-cell is operated and exerts a catalytic action, transforming the hypochlorite to chlorate when heat is subsequen tly supplied.

I may produce hypochlorites in a similar manner to the production of electrolytic bleach liquors and convert the h pochlorite to chlorate afterelectrolysis by mating the solution in the presence of chloriu or when mixed with chlorin or other suitable catalytic agent or carrier of oxygen.

My invention, therefore, is not limited to solutions containing chromates or bichromates, but is applicable to chlorid solutions alone or solutions containing a small amount of alkali, such solutions being capable after electrolysis with carbon or gra )hite anodes in contradistinction to by )oc lorite solu tions produced by other t an electrolytic methods of direct and substantially quantitative conversion into chlorate by application of heat:

l I i l i r described.

3. The method which consists inelectrolyzing a solution containing a chlorid and a compound of chromic acid with a carbon or graphite anode, at such temperature as to substantially avoid disintegration of the anode, and then heatin the resulting solution out of contact wit the anode to produce chlorate, substantially as described.

4. The method which consists in electrol zing a solution containing a chlorid in a diaphragm-cell with a carbon or graphite anode, at such temperature as to substantially avoid disintegration of the anode; and then heating the resulting solution out of contact with the anode to produce chlorate, substantially as described. 7

5.. The method which consists in electrolytically producing hypochloritcs, then converting' the same to chlorate by heating the solution in the presence of a chromie-acid compound out of contact with the electrodes, substantially as described.

6. The method which consists in heating a solution containing a hypochlorite-and a comound of chromic acid, andthe'reby transormihg the hypochlorite." t'o chlorate; substantially as described.

In testimony whereof I havehereunto set my hand.

ARTHUR EDWARD GIBBS. Witnesses:

LILLIAN GrERTRUDE SMrrn, EMMONs BRYANT.

It is hereby certified that in Letters Patent No. 827,721, granted August 7, 1906 upon the application of Arthur Edward Gibbs, of Niagara Falls, New York, for an improvement in Processes of Producing Salts of Oxyacids'of Ohlorinfian error I appears in.the printed specification requiring correction, as follows: In line 11, page 1,

} the word chlorin shouldread chlorid; and that the said Letters Patent should be read with this correction therein that the same may conform to the record ot' the cats in the Patent Office.

illgnc-(l and sealed this 28th day-oF-August, A. ,D.. 1906.

E. B. Moon's,

Acting Commissioner of Patenti.

Letters Patent No. 827,721.

' been converted to bichromate.

- chromate according to the following equa- ."ec' ion in tion:

2KHO+ KZCrZOT QKA 1101+ H2O.

In this way the birhromaie ma be continually changed tO C-lllfilllittfi wit 10111: the increase of either in solution while the chlorate formation proceeds. The presence of a chromium compound is not absolutely necessary to produce a high elliciencv. may have present a trace of a chlorid, the h drate of the metal with which it is combiner being sparingly soluble or insoluble in thes0lution-- for instance, calcium ehloridand conducting the electrolysis at a'temperature preferably below 37 centigrade, raisim the temperature oi the solution after electrolysis.

lhe calcium hydrate being practically insoluble is deposited at the cathode, leaving its chlorln free at the anode. 'lhis chlorm dissolves in the solution at the temperature at which the-cell is operated and exerts a catalytic action, transforming the hypochlorite to chlorate when heat is subsequen tly supplied.

I may produce hypochlorites in a similar manner to the production of electrolytic bleach liquors and convert the h pochlorite to chlorate afterelectrolysis by mating the solution in the presence of chloriu or when mixed with chlorin or other suitable catalytic agent or carrier of oxygen.

My invention, therefore, is not limited to solutions containing chromates or bichromates, but is applicable to chlorid solutions alone or solutions containing a small amount of alkali, such solutions being capable after electrolysis with carbon or gra )hite anodes in contradistinction to by )oc lorite solu tions produced by other t an electrolytic methods of direct and substantially quantitative conversion into chlorate by application of heat:

l I i l i r described.

3. The method which consists inelectrolyzing a solution containing a chlorid and a compound of chromic acid with a carbon or graphite anode, at such temperature as to substantially avoid disintegration of the anode, and then heatin the resulting solution out of contact wit the anode to produce chlorate, substantially as described.

4. The method which consists in electrol zing a solution containing a chlorid in a diaphragm-cell with a carbon or graphite anode, at such temperature as to substantially avoid disintegration of the anode; and then heating the resulting solution out of contact with the anode to produce chlorate, substantially as described. 7

5.. The method which consists in electrolytically producing hypochloritcs, then converting' the same to chlorate by heating the solution in the presence of a chromie-acid compound out of contact with the electrodes, substantially as described.

6. The method which consists in heating a solution containing a hypochlorite-and a comound of chromic acid, andthe'reby transormihg the hypochlorite." t'o chlorate; substantially as described.

In testimony whereof I havehereunto set my hand.

ARTHUR EDWARD GIBBS. Witnesses:

LILLIAN GrERTRUDE SMrrn, EMMONs BRYANT.

It is hereby certified that in Letters Patent No. 827,721, granted August 7, 1906 upon the application of Arthur Edward Gibbs, of Niagara Falls, New York, for an improvement in Processes of Producing Salts of Oxyacids'of Ohlorinfian error I appears in.the printed specification requiring correction, as follows: In line 11, page 1,

} the word chlorin shouldread chlorid; and that the said Letters Patent should be read with this correction therein that the same may conform to the record ot' the cats in the Patent Office.

illgnc-(l and sealed this 28th day-oF-August, A. ,D.. 1906.

E. B. Moon's,

Acting Commissioner of Patenti.

rec-lion in Letters Patent No. 827,721.

It is hereby certified that in Letters Patent No. 827,721, granted August 7, 1906 I upon the application of Arthur Edward Gibbs, of Niagara Falls, New York, for an improvement in Processes of Producing Salts of Oxyacida'of Chlorin, an error app-am in.tlm printed specification requiring correction, as follows: In line 11, page 1, the word chlorin should read chlorid; and that the said Letters Patent should bn rmul with this corrootiou therein that the some may conform to the record of the 0216' in the Patent Office.

Higlmll mid :zvulud this 28th day of August, A. D. 1906.

HI-huh] E. B. MOORE, 

